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9.2.3. Digital Filter
Caution : • Inserting multiple filters may cause phase inversion of velocity loop in some
systems, resulting in unstable operation.
• Do not insert more than two filters. Setting a filter frequency too low may
cause hunting, etc.; set the frequency to 100 Hz or above.
Parameters for digital filter setting
u
Parameters : FP, FS, NP, NS
l
Sets filter frequency in the velocity loop.
l
The filters are useful for eliminating audible noise and vibration due to mechanical resonances.
Table 9-12: Parameter function
Parameter
Function
Shipping set
FP
Sets the primary low-pass filter frequency.
FP0
FS
Sets the secondary low-pass filter frequency.
FS0
NP
Sets the primary notch filter frequency.
NP0
NS
Sets the secondary notch filter frequency.
NS0
l
Refer to “12. Command and Parameter” for more details.
Figure 9-28: Digital filter block diagram
Velocity
command
Velocity
loop gain
Velocity data
Velocity loop
integrator
Primary
low-pass
filter
Secondary
low-pass
filter
Primary
notch
filter
+
–
Secondary
notch
filter
NS
NP
FS
FP
VI
VG
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